Coupling for line space wheels



Sept. 11, 1951 K. GEBHARDT COUPLING FOR LINE SPACE WHEELS Filed Feb. 24, 1949 Invenfar Patented Sept. 11, 1951 COUPLING FOR LINE SPACE WHEELS Konrad' Gebhardt, Nuremberg, Germany, assignor to Firma `Triumph-Werke Nrnberg A. G., Nuremburg, Bavaria, U. S. Zone, Germany ApplicationFebruary 24, 1949, Serial No. 78,189 In Germany October 1, 1948 l 6- Claims.

l This invention relates'to certain improvements in the device for coupling `the platenl or cylinder with the platen ratchet in typewriting, calculating and similar machines. In machines of this kind, the platen gear ywhich isI freely rotated with respect to the platen, can be coupledwith the platen by a `member engaging in an internal toothing thereof.

, The conventional `couplings for` platen ratchets have the `drawback that incase of Aa greater torque. to be transmittedrto the platenthe member engaging in the internal toothing of the platen gear is automatically disengaged, thus causing an unintentional line shifting. "It has been attempted to remove this defectby heavy springs. However, the operation of the line space release at the platen is rendered substantially more diicult thereby.

It is the object of the present invention to avoid these drawbacks of the existing devices.

With this object in view, according tothe present invention the disengaging pressure acting uponthe locking member isftaken up "bya supportingblockor bearing. Thus, kautomatic disengagement is prevented. The' locking member inthis case consists of af one-armed lever provided with an oblique-slot,vin'-whichismoved a clamping angle or sheet metal-adapted to be voperated by the shaft of the line spacelreleaseV de- Vice, and acting. as `a locking member bearing Vagainst the supporting block. Oneofthe legs of the clampingangle is provided with-a `slot closed on all sidesfor the passage of theportion of the locking member which defines thev radially inner edge. of the slot therein. Said leg is under action of a compression springf pressing. it nauto-- matically into its lockingposition. A separate clamping angle is provided for each locking member. Thus it is ensured that in case of .locking members cooperating with (n+1) or (n-l) teeth of the internal toothing of the platenrgear there is always one in Xed engagement while the others bear on the flank or on one of the edges of the internal toothing by action of:the spring of the clamping angle. The device according to the invention permits the use of a relatively weak spring for the clamping angle, since it serves merely to cause the clenching without being exposed to the releasing pressure.

The invention will be better understood by reference to the following detailed descriptionin connection with the accompanying drawing showing by way of example and purely'schematically'one embodiment of the invention and in which:

Fig. 1 is a cross sectional View of the device,

Fig. 2 is a'fragmentary cross section through a locking member in its engaged position, on a larger scale,

Fig. 3 is a section similar to Fig. 2, with the locking member disengaged,

Fig. 4 is a View on the front side with the platen shaft and covering disk taken oir and the locking members disengaged, on a larger scale,

Fig. 5 is a view according to Fig. 4 with the locking members engaged;

Fig. 6 is a view of the clamping angle member.

Similar reference numerals denote similar parts in the different views.

Referring now to the drawing in greater detail, and first to Fig. 1, it will be seen that the platen I at its left face bears a covering cap 2 to which the end capsule 4 and the wedge guide `member 5 acting as a supporting block aresecured. Secured-.to .the Ybottom'of-the end capsule# is the holder G for the locking members 'I formed as single-armed wedge levers, by means of screws 8. Swingably mounted on the bent off bearing eye 9 of holder 6 at Ill, are the wedge 'levers l, being secured against lateral deflection inthe appertaining slots II of the wedge guide member 5 and'formed with an oblique slot I6 defined at its radially inner edgeby members I'I, Figs. 2 and 3. In the end capsule 4 the clamping angles I3 are introducedthrough bolts I4. In their bent oil portion 30 the angles I3 are formed with a recess 3l, Fig. 6, for iorming'the bridge I5, which engages the inclined slot IS of the wedge lever 1, the clamping angle I3 bearing against the cylindrical surface I8 of the wedge guide 5, Figs. 2 and 4. This arrangement forms a friction ratchet preventing a rearward movement of the wedge lever T, while not offering any resistance as the clamping angle I3 is pressed back, except for the counterpressure of the springs I2, so that it can easily be released.

The platen gear I9 into whose internal toothing 20 one of the wedge levers 'I is pressed under action of spring I2, is mounted for rotation on the wedge guide member 5 Aand kheld by the closure disk 22 xed by screws 2|. Screwed into the Wedge guide member 5 is the left hand platen shaft 23with'the platen knob 24 secured thereto.

'Slidably mounted in the platen shaft 23, against action of spring 2l, and secured on the adjusting-screw 29, Fig. l, by the nutv 28, is the cylinder release shaft 25 with its "cylinder release buttonZE. 1

The device acts as follows:

In order to release the platen gear coupling, the button 26, Fig. 1, is pressed inwardly, thereby forcing back the clamping angles I3, by the head of the adjusting screw 29, against action of the springs l2. The bridges I of the clamping angles I3 in this case slide in the slots I5 of the wedge levers, swinging them inwardly. The platen gear I9 is now released and the platen can be freely turned, Figs. 3 and 4.

If the cylinder release button 25 is again released after adjustment of the platen I, the shaft 25 of the cylinder release device is again returned to its normal position, byspring 27, thereby also moving forward the clamping angles I3 by the springs I2, so that the wedge levers 'I are swung outwardly, through bridges IS, into engagement with the internal toothing 2Q of the platen gear I 9, Figs. 1, 2, and 5.

As will be seen from Fig. 5, the platen gear I9 can be safely locked in any position of the platen I. The reliability of this locking, as already mentioned, is due to the fact that each of the three wedge levers 1 is held engaged with the internal toothing 2! of the platen gear I9, by a separate clamping angle I3 for each lever l, the clamping angles I3 owing to their vertical position on the cylindrical part I 8 of the wedge guide member 5 forming a reliable frictional locking device having a self-locking effect, by cooperation of the various parts.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

l. In line spacing mechanism for typewriting, 'calculating and similar machines, in combination with a platen and a line space release shaft, a gear with internal toothing mounted for free rotation on the platen, locking members adapted to engage in said internal toothing for effecting the coupling connection, each locking member having an inclined operating slot, operating means adapted to be moved in said slots under action of the line space release shaft for engaging and disengaging said locking members, and supporting means adapted to take up the pressure acting radially inwardly upon said'operating means as a result of the disengaging tendency of the locking members, said locking members, operating means, and supporting means being combined and interrelated in such a way that said inwardly acting radial pressure causes a self-locking friction preventing inadvertent disengagement of the locking members.

2. In line spacing mechanism for typewriting, calculating and similar machines, in combination with a platen and a line space release shaft, a clutch mechanism comprising a gear with internal toothing mounted for free rotation on the platen, a plurality of one-armed levers each having an inclined slot and adapted to engage in said internal toothing for effecting the coupling connection, clamping angle means adapted to be moved in said slots under action of the line space release shaft, and supporting means adapted to take up the pressure acting radially upon said clamping angle means as a result of the disengaging tendency ofi the levers.;

3. In line spacing mechanism for typewriting, calculating and similar machines, in combination with a platen and a line space release shaft, a `clutch mechanism comprising a gear with internal toothing mounted for free rotation on the platen, a plurality of one-armed levers each having an inclined slot and adapted to engage in said internal toothing for effecting the coupling connection, clamping angle means for each lever adapted to be moved in the slot of said lever under action of the line space release shaft, one leg of the clamping angle means associated with each lever being provided with a second slot closed on all sides for the passage of a portion of Said lever defining the radially inner edge of said inclined slot, and supporting means adapted to take up the pressure acting radially upon said clamping angle means as a result of the disengaging tendency of the levers.

4. In line spacing mechanism for typewriting, calculating and similar machines, in combination with a platen and a line space release shaft, a clutch mechanism comprising a gear with internal toothing mounted for free rotation on the platen, a plurality of one-armed levers each having an inclined slot and adapted to engage in said internal toothing for effecting the coupling connection, clamping angle means having operating legs each adapted to be moved in its associated inclined slot under action of the line space release shaft, each operating leg being provided with a second slot closed on all sides for the passage of a portion of the associated lever forming the radially inner edge of the inclined slot in said lever, compression spring means acting upon the clamping angle means in the direction for engagement of said levers, and a central supporting cylinder adapted to take up the pressure acting radially upon said clamping angle means as a result of the disengaging tendency of the levers.

5.-In line spacing mechanism for typewriting, calculating and similar machines, in combination with a platen and a line space release shaft, a clutch mechanism comprising a gear with internal toothing mounted for free rotation on the platen, a plurality of one-armed levers each having an inclined slot and adapted to engage in said internal toothing for effecting the coupling connection, a clamping angle for each lever adapted to be moved in the slot of said lever under action of the line space release shaft, one leg of each clamping angle being provided with a second slot closed on all sides for the passage of a portion of said lever forming the radially inner edge of said inclined slot, and a common central supporting cylinder adapted to take up the pressure acting radially upon each clamping angle as a result of the disengaging tendency of its lever.

6. In line spacing mechanism for typewriting, calculating and similar machines, in combination with a platen and a line space release shaft, a clutch mechanism comprising a gear with internal toothing mounted for free rotation on the platen, a plurality of one-armed levers each having an inclined slot and adapted to engage in said internal toothing for eiecting the coupling connection, clamping angle means adapted to be moved in said slots under action of the line space release shaft, and supporting means adapted to take up the pressure acting radially upon said clamping angle means as a result of the disengaging tendency of the levers, the slope of the inclined slots being such as to cause a self-locking eiect against disengaging action.

KONRAD GEBHARDT.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Numbei' Name Date 1,764,224 Pateman June 17, 1930 1,955,912 Harney Apr. 24, 1934 FOREIGN PATENTS Number Country Date `596,272 France of 1925 

